Composition-filled brake-shoe.



H. JONES. COMPOSITION FILLED BRAKE SHOE. APPLICATION IILBD JULY 2, 1912.

1,082, 1 58, Patented Dec. 23,1913.

lnvcn or:

UNITED sTAtrEsPATENT oFFioE.

HARRY JONES, OF SUFFERN, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO AMERICAN BRAKE SHOE & FOUNDRY COMPANY, OF MAHWAH, NEW JERSEY, A

CORPORATION OF NEW JERSEY.

- COMPOSITION-FILLED BRAKE-SHOE.

Specification of Letters Patent.

' Patented Dec. 23, 1913.

Application filed July 2, 1912. Serial No. 707,223.

To all whom it may concern certain new and useful Improvements in Composition-Filled Brake-Shoes, of which the following is a specification.

My invention relates to an improvement in brake shoes, and more particularly to that kind or type usually known and referred to as filled shoes and wherein is employed a casing for containing a composition body.

Heretofore, it has been deemed advisable to construct this containing shell or casing of a ductile metalsuch as malleable iron, wrought iron, or steel, and in some instances of cast malleable iron. From numerous experiments, however, I have found that by so doing, the actionof the wheel upon the shoe tends to heat the edges of the shell .and cause the metal to spread or flow, and thus to a certain extent reduce the area of the composition body contacting with the wheel. Furthermore, the extreme heat hardens or tempers the edges of the shell, causing the latter to cut and score the wheel tread, and in some instances burn the particles of metal forming the edges of the shell, which becoming detached, also assist in scoring and injuring the tread of the wheel. In order to avoid these objections, I have learned from experiment that the best results are obtained by forming the shell from a metal which, when cold, will be tough and strong,

yet when heated will become extremely brit tle and rapidly disintegrate when in service. To accomplish this result I have employed iron and steel having a small amount of sulfur contained therein, as I have found in practice that such metal is sufficiently strong when in a cold state to withstand any strains that might be imposed upon it while filling the shell with the composition to form the body, but which, when highly heated by frictionah contact with the wheel, will become very brittle, and while in service rapidly disintegrate, crumbling away simultaneously with 'the wearing away of the composition body, thereby preventing any injury to the tread of the wheel, and at the same time permitting the entire area of the wearing face of the composition body to contact with the wheel.

In an application for Letters Patent for an improvement in composition filled brake shoes filed by Joseph D. Gallagher and me as Joint inventors upon the second day of July, 1912, Serial Number 707,249, various I metals, mixtures, and alloys this purpose are referred to, and there is broadly claimed therein a shoe comprising in part ashell made from a metal having the characteristics above mentioned, viz., tough and strong while in a cold state, and extremely brittle while in a heated state. In this application, however, I have limited my claim to a metal having the above characteristics produced by the employment of sulfur. in the metal.

In the drawing accompanying and forming a part of this application: Figure 1 is a view showing a section upon a longitudinal central plane of a brake shoe of the type to which my invention relates; and Fig. 2 is a view showing a section of the same upon available for a transverse plane indicated by the line 22, Fig. 1.

Referring to the drawing, the external metallic shell or casing is designated by the reference character 3. This shell is formed from sheet metal having a thickness of about to l, by means of suitable forming dies and by bonding or pressing operations. The sheet metal employed will be of the ordinary commercial variety from which 1 sulfur has been eliminated during the process of manufacture, for should sulfur be present in the sheet metal it cannot be successfully shaped by dies in a heated condition due to the brittleness of iron containing sulfur when heated to a red heat or higher.

After the shell or casing has been given the form and shape required in the finished shoe, a quantity of sulfur-sutlicient to render the shell brittle when heated by frictional contact with the car wheel is imparted to the finished shell, so that the shell will rapidly disintegrate when the shoe is in service. This may be accomplished in several ways, as by heating the shell and exposing it to sulfur in a vaporous form, or by packing the finished "shell in sand or loam with which sulfur has been mixed and'heating the same, in both of which cases the shell is annealed and sulfur imparted thereto at a single operation.

' plained braking effect will be due to the filling. The

be of various materials, or may be com-- osed of various ingredients. I recommend,

owever, a composition made up of the fol lowing ingredients, as with it I have secured satisfactory results.

Fire clay 1 part Iron borings 3 parts Crushed iron ore 3 parts Coal tar 1 part Asphalt part the ingredients being thoroughly mixed and heated to about 112 F. and pressed into the casing. V

\Vhen a brake shoe formed as above exis in use substantially the entire edges of the shell, however, contact with the tread of the \vheeland are heated by friction due to contact therewith, to a degree such that the metal of the shell loses the qualities of toughness and ductility possessed by it when cold, and acquires properties, or reaches a condition such that it will rapidlydisintegrate when the shoe is in service, thus preventing a flow of the metal to form a serrated or feathered edge, as would be the case if the metal retained its ductility at high temperatures.

It will he understood that the basic metal of the shell above referred to is preferably iron, and that the property by virtue of which the iron becomes brittle at a high temperature, so that it will disintegrate readily, is due to sulfur associated therewith in the specific embodiment of my invention describedand claimed in thisapplication,al-

though a variable amount of carbon is also usually present whereby'the metal pal-takes more or less of the characteristics of steel.-

' The quantity of sulfur contained in the metal from which the 'shell is made may vary, the amountthereof being such as is recognizedby authorities on iron and steel as being sufiicient to render the same brittle when heated, or hot short, for instance from .05% to .1570, or thcreabout.

Having. thus described and explained my invention, I claim and desire to secure by Letters Patcnt:

1. A brake shoe comprising a composition wearing body, and a shell containing said body, said shell being formed from metal, and to which finished shcll'sul-fur is added in such quantity as to-render the same brittle when in a heated condition, wherehy it will rapidly disintegrate when the shoeis in service.

2. A brake shoe comprising a composition wearing body, and a shell to contain said body, said shellbeing formed from a metal low in sulfur, and to which shell, in its finished form, is added sulfur in quantities sufiicient to render the same extremely brittle when heated, whereby said shell will rapidly disintegrate when in contact with the tread of a wheel. A

Signed at New York, borough of Man the county of New York and State hattan, in of New York, this 27" day of June, A. D. 1912.

HARRY JONES.

YVitnesses A. V. \VALsH, H. M. WHITE. 

